完善后台管理与测试支撑

1、为后台用户列表增加关键词和状态筛选，后端同步支持过滤与总数统计。

2、创建用户时要求填写初始密码，并补充前端校验和自动填充隔离。

3、优化项目管理列表角色展示、项目详情抽屉脏数据保护和审计详情抽屉关闭体验。

4、清理旧费用附件关联、统一测试模型注册，并更新迁移端点和注册筛选测试。

frontend/src/views/admin/Users.vue

@@ -65,11 +65,12 @@
               clearable
               class="filter-input-comp"
               :prefix-icon="Search"
-              @keyup.enter="loadUsers"
+              @clear="applyFilters"
+              @keyup.enter="applyFilters"
             />
           </div>
           <div class="filter-item-form">
-            <el-select v-model="statusFilter" :placeholder="TEXT.common.fields.status" style="width: 140px" clearable class="filter-select-comp" @change="loadUsers">
+            <el-select v-model="statusFilter" :placeholder="TEXT.common.fields.status" style="width: 140px" clearable class="filter-select-comp" @change="applyFilters">
               <el-option :label="TEXT.enums.userStatus.PENDING" value="PENDING" />
               <el-option :label="TEXT.enums.userStatus.ACTIVE" value="ACTIVE" />
               <el-option :label="TEXT.enums.userStatus.REJECTED" value="REJECTED" />
@@ -77,7 +78,7 @@
             </el-select>
           </div>
           <div class="filter-item-form">
-            <el-button @click="loadUsers" :icon="Refresh">{{ TEXT.common.actions.search }}</el-button>
+            <el-button @click="applyFilters" :icon="Refresh">{{ TEXT.common.actions.search }}</el-button>
           </div>
           <div class="filter-spacer"></div>
           <el-button type="primary" :icon="Plus" @click="openCreate">{{ TEXT.common.actions.add }}{{ TEXT.modules.adminUsers.userLabel }}</el-button>
@@ -249,6 +250,11 @@ const loadUsers = async () => {
   }
 };
 
+const applyFilters = () => {
+  page.value = 1;
+  loadUsers();
+};
+
 const onPageSizeChange = (size: number) => {
   pageSize.value = size;
   page.value = 1;